Specified data for tonsil surgery in Germany

Background: Tonsillectomy rates vary considerably among different states, regions, and times. This study was conducted to identify the prevalence of “chronic” tonsillitis, peritonsillar abscess, hypertrophy of the tonsils with and without adenoids in absolute and relative numbers in an 80 million people nation. Moreover, the number and rates of different surgical procedures to resolve either “chronic” tonsillitis, peritonsillar abscess, or upper airway obstruction due to (adeno)tonsillar hypertrophy over several years was evaluated in this study (tonsillectomy, adenotonsillectomy, tonsillotomy, abscess tonsillectomy, transoral incision and drainage). Finally, the post-tonsillectomy hemorrhage rate was calculated and analyzed in relation to age and gender. Material and methods: Calculations were based on data as published by the Federal Institute of Statistics or on request, if needed. The latest data were provided for 2013. Results: The total number of the aforementioned diseases (stratified by ICD-10) decreased from 142,574 (in 2000) to 87,624 in 2013 (38.5%). Tonsillectomy, with or without adenoidectomy, was performed in a total of 833,896 patients between 2006 and 2013 in Germany. The yearly number decreased continually from 120,993 in 2006 to 84,332 procedures in 2013 (30.3%). The most significant decrease was registered in patients younger than 20 years of age for this time period: 70.92 per 10,000 in 2010 to 58.68 per 10,000 in 2013. If all age groups were included, the rate decreased from 13.34 per 10,000 to 10.90 per 10,000. In contrast, an increasing number of tonsillotomies was observed between 2007 (4,659 procedures) and 2013 (11,493). The cumulated number of procedures was 59,049. A constant number of 15,000 cases with peritonsillar abscess were diagnosed per year in Germany (19 patients per 100,000). The prevalence increased significantly at an age of 15 years and there was a preponderance of female patients below that age. Compared to the transoral incision and drainage, a 2.8-fold greater number of abscess tonsillectomies were performed annually. Post-tonsillectomy hemorrhage was experienced in 5.98% of all patients after 245,721 procedures in 2010 and 2013 (all indications, except tonsillotomy). Bleeding complications had occurred less frequently in female patients (5.06% vs. 7.02%). Finally, a considerable increase of post-tonsillectomy hemorrhage in patients older than 10 years of age was registered in male patients only. Conclusion: Chronic tonsillitis was less frequently diagnosed and surgically treated in terms of tonsillectomy (with or without adenoidectomy), particularly in female patients. In contrast, the number of tonsillotomies increased continually, particularly in male patients. Peritonsillar abscess was diagnosed and surgically treated in a constant number of patients in the yearly comparison. Most of these patients were scheduled for abscess tonsillectomy, and only a 2.8-fold smaller number for transoral incision and drainage. Independent from the indication for surgery, post-tonsillectomy hemorrhage was clearly associated with male gender and age (>10 years). The study reveals a dramatic change mandating further surveillance in insurance companies and authorities in the national health system of an 80 million people nation. (Tab. 1)

: Population and age structure in Germany [23] 1 Introduction In 2004, Van Den Akker et al. [1] reported of different tonsillectomy rates in different countries and in the time course. The rate varied between 19 (Canada) and 118 (Ireland) per 10,000 children as well as 19 (Canada) and 76 (Finland) per 10,000 adolescents. In the Netherlands, the rate decreased from 290 in 1974 to 96 in 1985 per 10,000 children, and between 1985 and 1995 it increased from 20 to 43 per 10,000 adolescents. In Great Britain, the rate had increased from 50 in 1980ies to 80 in the 1990ies per 10,000 children and from 22 in 1980 to 30 in 1995 per 10,000 adolescents [1]. The different frequency was notified on a national and regional basis of different countries [2], [3], [4], [5], [6], [7], [8], [9], [10], [11] and during time periods of the same region [11], [12]. Concerning tonsillectomy (TE), age-related differences are accompanied by increasing rates of tonsillotomy (TOTO) -at least in Sweden, Austria, and Germany - [10], [13], [14]. The present study aimed to answer the following questions for Germany: • How many patients were treated for chronic tonsillitis, tonsillar hypertrophy, and adenotonsillar hypertrophy on an inpatient basis? • How many patients were scheduled for TE and TOTO per year? What are the rates per 100,000 inhabitants? • What is the rate of post-tonsillectomy hemorrhage?
Are age and gender risk factors for post-tonsillectomy hemorrhage? • How many patients were treated for peritonsillar abscess (PTA) and many patients underwent surgery (abscesstonsillectomy or transoral incisional drainage)?
On the other hand, individually ordered evaluations based on the 6-digit OPS code were used. The Federal Statistical Office provides a variety of tables with the possibility to change variables like diagnosis, gender, years and so on [21]. The changes can be seen immediately online, but the results cannot be cited as an URL in this paper due to their temporary character. Comparable registers for outpatient procedures, such as TOTO, do not exist. The performance of "tonsillotomy" is not part of the official outpatient performance catalogue (annex 2 of the Physicians' Fee Scale; Einheitlicher Bewertungsmaßstab, EBM). This catalogue dictates which kind of procedure has to be performed on an outpatient basis. Unfortunately, these procedures have a different code and they are not reported to the Federal Statistical Office. Instead, there are special TOTO contracts and thus a large number of regionally agreed scales of fees where one cannot be sure what the service exactly is or which position corresponds to which performance. Furthermore, the exact scope of the agreements is not known [22]. Several calculations with regard to the total population in Germany were based on the data published by the Federal Statistical Office that are listed in a table considering partly the age structure (Table 1) [23].

Prevalence
The most recent data on patients treated on an inpatient basis were issued by the Federal Statistical Office in 2013. In this particular year, a total of 578,440 inpatients were treated for ENT-specific diseases [24].  A differentiation of the single diagnoses of chronic tonsillitis, hypertrophy of the palatal tonsils with and without hypertrophy of the pharyngeal tonsil, hypertrophy of the pharyngeal tonsil as well as other chronic diseases of the palatal and pharyngeal tonsils based on the 4-digit ICD-10 code is described in Figure 1. For this diagnosis, the comparison of 2000 and 2013 revealed a reduction of the number of inpatients by factor 1.37. The difference between male and female patients was not significant-in contrast to "chronic tonsillitis". The decrease of the diagnostic frequency affected both, male and female, equally. In 2004 and 2013, one death was registered in each year. In the evaluation period, the average number of inpatient stays had decreased from      (Table 2).  Figure 7).  There was only a slight tendency of a decreasing frequency and ranking among the 50 most frequent interventions in male patients. It is therefore very likely, that the decreasing total frequency resulted from the group of female patients ( Figure 8).

Prevalence in female patients between 2005 and 2013 (OPS code: 5-281)
A significant decrease in the numbers of procedures and ranking was registered in female patients since 2005. However, the number of female patients exceeded the one of male patients every year ( Figure 9).

Rate of tonsillectomy in younger patients (<20 years)
The evaluations for 2010 and 2013 enabled the author to calculate the rate of TE for patients <20 years of age due to the available population numbers in Germany, as published by the Federal Statistical Office [23]. Obviously, more female patients had undergone TE in this age group. The absolute number of interventions had decreased by 19.6% and the rate by 17.3% within 3 years (Table 3 and  Table 4).       Table 3, the rates of tonsillectomy for patients younger than 20 years could be calculated for 2010 and 2013 with relation to the population statistics. Within 3 years, the rate had decreased by 17.3%.

Number of procedures between 2006 and 2013
The numbers of this intervention are obtainable from publications of the Federal Statistical Office since 2006, based on the 4-digit OPS code [15], [16], [17], [18], [19], [20]. The most recent data were available for 2013. Within the evaluation period, a total of 283,787 interventions had been performed (Table 5).

Adenotonsillectomy (OPS code: 5-282), stratified by age, between 2006 and 2013
The yearly number of procedures was retrieved from the Federal Statistical Office database, based on the 4-digit OPS code with most recent data available for 2013. After stratification into age groups, a significant reduction was obvious for the group of patients younger than 15 years ( Figure 12).       The prevalence varies between 17.94 and 19.6 per 100,000 inhabitants (Table 6) which is always less than the sum of abscesstonsillectomy and incisional drainage on a yearly analysis. This might result from a coding problem: peritonsillitis and PTA are coded as J36. It is also possible that alternative procedures such as interval tonsillectomy or needle aspiration or antibiotic alone were applied for a number of cases (      The graphs indicate the prevalence (y-axis) between 2005 and 2013 (x-axis), stratified by age groups (x-axis). It can be noticed that most interventions were performed in adolescents and young adults (15 to 25 years of age) and a decreasing number of cases within the evaluation period in this age group. The prevalence increases abruptly after the age of 15 and is continually decreasing after the age of 25. The prevalence differs significantly to the prevalence of the diagnosis "chronic diseases of the palatal and pharyngeal tonsil".
• Highest frequency between the ages of 15 and 25 (risk group) • Decreasing prevalence within the evaluation period in the risk group • Sudden increase of the prevalence in patients older than 15 years of age • Continuously decreasing frequency in patients older than 25 years of age • Age-specific prevalence different to "chronic diseases of the palatal and pharyngeal tonsils" (ICD-10: J35)

Abscesstonsillectomy, male vs. female patients 3.5.4.1 2010 [26]
A specified analysis on request by the author [26] confirmed the finding, that patients younger than 20 years of age were mostly female and patients older than 20 years of age were male (Figure 21).

2010 [26]
With the exception of patients between 10 and 14 years of age, patients of all age groups were predominantly of male gender. This contrasts to the finding for abscesstonsillectomy ( Figure 23).

Male patients in 2013 [26]
The data of 2013 confirm the conclusions drawn for 2010 ( Figure 26).

) in female patients in 2013
The graphs indicate the prevalence (y-axis) of both interventions stratified by age groups (x-axis). Abscesstonsillectomy prevailed and incisional drainage was performed to a significant extent only after the age of 15 years. w = female

Female patients in 2010
Abscesstonsillectomy prevailed as treatment modality with incisional drainage increasingly performed beyond the age of 15 (Figure 27).

Female patients in 2013 [26]
The data of 2013 confirm the conclusions drawn for 2010 ( Figure 28). In female patients, a bleeding rate of 5.02% (3,530 events) was calculated after 70,292 procedures. Unfortunately, a limitation to bleeding events after elective TE (OPS code: 5-280.0) and thus a correlation is not exactly possible because bleeding complications might also have occurred after abscess, revision, or transpharyngeal TE as well as TOTO, but were assessed via the identical OPS code (5-281.9). The graphical illustration shows clearly the age-dependent phenomenon of post-tonsillectomy hemorrhage in male and female patients up to the age of 15, continually increasing only on male until the age of 30 years, while the rate remains almost unchanged in female patients (Figure 29).

Post-tonsillectomy hemorrhage rate in 2013 [26]
After 54,259 interventions in male patients (coded as mentioned in 3.6.1), a bleeding rate of 6.99% was calculated based on 3,796 events. For female patients, a postoperative bleeding rate of 5.11% (3,088 events) was calculated after 60,376 procedures. The phenomena described for 2010 were confirmed including a pronounced age-related bleeding rate up to 15 years in female and 30 years in male patients ( Figure 30).

Tonsillectomy
The role of TE within the public health system has been described in a previous paper, published in 2013 [27]. In 2010, ENT related interventions such as septoplasty, surgery of the nasal turbinates, TE, and neck dissection ranked among the 50 most frequently performed inpatient procedures in hospitals [21]. TE and ATE amounted to 128,133 interventions in 2010 which is equal to the numbers of cataract surgery (rank 24). Until the age of 14 years, ATE is the most frequently performed intervention in girls (12,094) and boys (13,724) [18]. A comprehensive analysis of national data in Germany was only recently published [10]. The analysis revealed variable regional differences in the prevalence of TE, ATE and TOTO according to an age and gender standardization. The 16 federal states were different with regard to the prevalence of TE in children and adolescents by factor 3, on the level of the 412 districts even by factor 8. This means that in some places only 1 of 900 children had undergone TE whereas in other regions 1 of 70 was scheduled for surgery. In relation to the indication "chronic tonsillitis" the difference was 12-fold and for "hypertrophy of the palatal tonsils" it was even 58-fold. However, a decrease in the prevalence was identified between 2007 and 2010 with an increasing number of TOTO procedures at the same time. This tendency was confirmed by the present study with a continuing decrease in the number of TEs and an increasing number of TOTOs in Germany [28].
As expected, the Bertelsmann study had triggered a great discussion about the current clinical practice in Germany. However, an attempt to compare the contemporary numbers with other nations is not obtainable from the literature. We therefore choosed to retrieve numbers from a database provided by the OECD (Organization for Economic Cooperation and Development) nations. This institution encompasses the following nations: Australia, Austria, Belgium, Canada, Chile, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Great Britain, Hungary, Ireland, Iceland, Israel, Italy, Japan, Korea, Luxemburg, Mexico, New Zealand, the Netherlands, Norway, Poland, Portugal, Turkey, and the USA. The data of these countries are open to online researches [29]. The respective calculations are possible by entering a key word such as tonsillectomy, total number of procedures, total procedures per 100,000 population, % performed as inpatient cases, all countries, from 2005 to latest available date [20]. It can be concluded from the OECD database, that TE is predominantly performed on an inpatient basis. The lowest rate of was found for the USA (3%), the highest rate Slovenia and Hungary (100%). In 2013, a total of 96.4% of the patients were hospitalized in Germany. Data from the Czech Republic, Greece, Iceland, Japan, Slovakia, Chile, and Estonia were not given. Based on calculations per 100,000 inhabitants, the lowest number of TE was registered in Mexico (23) and the highest number  51,983 (2003) [11], France: 50,000 children [35], Great Britain: 78,000 [36] and 90,000 [37], and USA: 1,400,000 (1959) and 500,000 (1979) [38], 286,000 (1994) [39], [40] as well as 287,000 children (1996) [41] and 530,000 children [42], [43], [44] and 250,000 [45]. Sometimes also data on TE rates are found, as for example for Italy with a TE rate of 10

Tonsillotomy
The increasing number of TOTO in Germany was first described by the Bertelsmann Company [10] and is confirmed by the present study. However, the increasing number of TOTO procedures does not completely compensate the decrease in the prevalence of TE and ATE. Unfortunately, the database of the OECD countries does not provide any information concerning TOTO. The Austrian TE study (with an undetermined number of outpatient TOTOs) revealed a TOTO:TE ration of 1:3.48 in 2010. In Germany, the ratio was 1:13.6 in 2010 and 1:8.5 in 2013.

Phenomena
1. Decreasing frequency of diagnosis Considering the frequency of diagnosis of "chronic tonsillitis", "hypertrophy of the palatal tonsils" as well as "hypertrophy of the palatal tonsils with hypertrophy of the pharyngeal tonsil", a decrease by factor 2.16, 1.37, and 1.53 was found for Germany between 2000 and 2013 which cannot be explained scientifically. This phenomenon has no justification in the population development in the same period. Moreover, no scientific argument is obtainable to explain the higher prevalence of "chronic tonsillitis" in female patients and an equal prevalence of hypertrophy of the tonsils/adenoids in boys and girls. An imbalanced gender ratio of the population does not exist, as shown in Table 9 [79].

Decreasing number of cases
Between 2005 and 2013, the number of TE in Germany decreased (without simultaneous AT) by factor 1.12. In female patients, this factor was higher (1.18) compared to factor 1.06 in male patients. The detailed analysis shows a significant decrease of the case numbers especially in the age group of 5-10 years as well as 15-20 years. This aspect can only be described as a phenomenon, but not explained scientifically.

Female preponderance
In the present study the male to female ratio was in total 1:1.29 for TE which differs to Great Britain (1:1.49) and in Austria (1:0.82) [79], [80]. The detailed analysis of two years, 2010 and 2013, revealed a striking difference in the prevalence of the TE and ATE between female and male patients, especially in the age group younger than 20 years. A twofold higher rate in female patients was determined in young adults (15 to 20 years of age) who had undergone TE. For ATE, the difference was even a threefold higher rate for the same age group which cannot be explained scientifically. This phenomenon has been described earlier for a population (n=10,095) of three German ENT departments with a significant different prevalence of TE particularly in younger patients (16 to 20 years of age) [81]. The authors suggested a specific psychic constellation in female patients at that particular age, but this hypothesis cannot be clarified retrospectively. However, the phenomenon described by Spicker and Schultz-Coulon was confirmed by the present study (n=627,874). It is noteworthy to repeat, that analysis of data retrieved from the Federal Statistical Office database could exclude an imbalanced gender distribution in the German population.

PTA
The sudden increase of the prevalence at an age of 15 years with a decrease at an age of 25 years cannot be explained scientifically. Moreover, the preponderance of female gender only at an age between 10 to 15 years remains a conundrum.

Limitations
Different entities may be summarized with a single ICD-10 code, impeding a differentiated analysis of the data provided by the Federal Statistical Office. "J35" is a good example for this problem (see 3.1.2) and may explain the two peaks in the prevalence related to age. "J35" includes "chronic tonsillitis" (ICD-10: J35.0), "hypertrophy of the palatal tonsils" (ICD-10: J35.1), "hypertrophy of the pharyngeal tonsil" (ICD-10: J35.2), "hypertrophy of the palatal tonsils and the pharyngeal tonsil", and "others", respectively. The data of all procedures performed on an outpatient are not registered by the Federal Statistical Office or any other institution. This unknown number of procedures was therefore not included in the present study. The concept of interval TE (elective TE after previous transoral incisional drainage) for PTA cannot be decoded because a coherent depiction of the single cases is virtually impossible.

Summary
The prevalence of chronic diseases of the palatal tonsils as well as the absolute and relative frequency of tonsillectomy has clearly decreased within the investigated time period, predominantly in female patients. In contrast, the number of TOTOs has increased continually, particularly in in male patients. Numbers and rates of different treatment modalities for PTA have not considerably changed. However, it appears as if incision and drainage has become a more popular intervention but abscesstonsillectomy clearly prevails. Regardless the indication for surgery, bleeding complications had occurred preferably in male patients, especially in adolescents and young adults.